Library apparatuses are used to store data in mass storage media such as magnetic tape. Storage media drives (simply “drives”) are installed on a library apparatus to read data from or write data to a plurality of storage media accommodated in the apparatus. When an access request arrives from, for example, a host computer or other higher-level device, the receiving library apparatus mounts a specified storage medium on one of the drives and executes read and write operations on the mounted storage medium. In this way, the library apparatuses enable a large amount of data to be stored and managed on a plurality of mass storage media.
Such library apparatuses have the functions of managing a plurality of storage media that may conform to different standards or different versions of the same standard. For example, one proposed method manages a plurality of tape cartridges on the basis of information collected from each tape cartridge, the information indicating with which standard specifications those tape cartridges comply. Another management method is to check the installation date of each storage medium with respect to the current date, thus determining whether its quality assurance period has expired. See, for example, the following patent literature:
Japanese Laid-open Patent Publication No. 2010-27189
Japanese Laid-open Patent Publication No. 2006-172400
The drives on a library apparatus may be changed to other drives for the purpose of maintenance or upgrade.
However, replacement of drives could introduce a compatibility problem into the library apparatus; it may become difficult to read and write data in some existing storage media. Suppose, for example, new drives are designed for the latest generation of storage media while not supporting some class of older storage media. In this case, the library apparatus becomes unable to read or write such old-generation media because of their incompatibility with the new drives. The library apparatus would fall into similar difficulties in the case where some existing drives are replaced with other drives of a different standard.